1. Field
The described technology relates generally to an electricity generator and a fuel cell stack.
2. Description of Related Art
An electricity generator includes a membrane electrode assembly (MEA) and a separator (also called a bipolar plate) coupled to the MEA.
Typically, the MEA includes an electrolyte membrane, an anode that is positioned at one side of the electrolyte membrane, and a cathode that is positioned at the other side of the electrolyte membrane. The separator forms a fuel channel at one surface toward the anode to supply fuel to the anode, and forms an oxidant channel at one surface toward the cathode to supply an oxidizing agent to the cathode. Electrical energy is generated by a hydrogen oxidation reaction of the anode and an oxygen reduction reaction of the cathode, and heat and water are additionally generated.
Further, non-reacted oxidant and non-reacted fuel that are not used for the oxidation reaction and the reduction reaction from the oxidant and the fuel that are supplied to the oxidant channel and the fuel channel, respectively, are discharged to the outside from the oxidant channel and the fuel channel. In this instance, the non-reacted oxidant and the non-reacted fuel may have a higher temperature because of the heat generated by the oxidation reaction and the reduction reaction than the oxidant and the fuel that are supplied to the oxidant channel and the fuel channel.
Therefore, the temperature of the separator at a region from which the non-reaction oxidant and the non-reaction fuel are discharged may become higher than at any other parts of the separator so the temperature distribution of the separator may not be uniform.
Further, the fuel cell stack includes a plurality of electricity generators, a pressurization plate for pressurizing and supporting the electricity generators, and a heat insulating member installed between the pressurization plate and the outermost electricity generator.
When the electricity generator generates electricity by the oxidation and reduction reaction, heat is also generated. In this instance, the temperature at the electricity generators provided in the center of the fuel cell stack can be higher than the temperature of the electricity generators that are provided near the heat insulating member. Therefore, the temperature distribution for the entire fuel cell stack may be non-uniform.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.